This invention relates to a molded article excellent in dimensional stability, physical strength and the like used for packaging a photographic film, etc., a manufacturing method and a package using the same.
Heretofore, molded articles for a photographic photosensitive material, such as spools for a 35 mm photographic film loaded in a cartridge, cores for a movie film, photographic film units with a lens, and cartridges for a photographic film, are formed of various resin compositions. For example, a spool for a 35 mm photographic film loaded in a cartridge (Japanese Utility Model KOKOKU No. 61-36995, etc.) is formed of polystyrene resin or high impact polystyrene resin, and a core for a movie film (Japanese Utility Model KOKOKU No. 2-37799) is formed of polypropylene resin, polystyrene resin, ABS resin or the like. A photographic film unit with a lens (Japanese Patent KOKAI No. 63-226643) is formed of high impact polystyrene resin having a low melt flow index blended with carbon black, and a cartridge for a photographic film (Japanese Patent KOKAI No. 1-312538) is formed of high impact polystyrene resin blended with carbon black.
However, the above molded articles for a photographic photosensitive material have various problems in their resin compositions.
That is, the resin composition used for the spool is inferior in moldability, heat resistance, dimensional stability and wear resistance, and occasionally affects photographic properties adversely. The resin composition used for the core for a movie film cannot be, in the case of a roll of a long length film, blended with an additive imparting slipperiness to the surface of the core such as a lubricant and a surfactant, because the roll tends to become into a form of cone, and accordingly, synthetic rubber or the like is added in order to prevent the slip of the rolled film. As a result, the resin composition is inferior in injection moldability and wear resistance. The resin composition used for the photographic film unit with a lens occasionally adversely affects photographic properties, and weld lines frequently occur to degrade appearance. Moreover, physical strength is low. The resin composition used for the cartridge for a photographic film is desired to improve photographic properties, heat resistance, appearance, physical strength and the like, and weld lines strongly occur. In brief, the resin compositions used for molded articles for a photographic photosensitive material are inferior in physical strength, photographic properties, injection moldability and the like.